A search is underway for two U.S. Navy pilots after their jet crashed near Washington State’s Mount Rainier, officials said.

The EA-18G Growler plane, based at Naval Air Station Whidbey Island, went down east of the mountain on Tuesday afternoon during a “routine training flight,” CBS News reported.

Navy officials told the outlet that multiple search and rescue assets have been deployed for the crew members, whose identities have not been released.

As of an 11:00 a.m. Wednesday KIRO7 report, the wreckage has not been found.

“Aerial operations continued through the night, launching from Whidbey Island and searching in the area 30 miles west of Yakima, Wash,” Naval Air Forces said in a statement to CNN on Wednesday. “Responders are facing mountainous terrain, cloudy weather, and low visibility as the search is ongoing.”

The Navy is working “in coordination with Yakima County tribal and local authorities” to locate the missing personnel, officials added.

The cause of the crash is under investigation, and the Federal Aviation Administration (FAA) has issued a flight ban around the search area, KIRO7 noted.

The downed aircraft is part of Electronic Attack Squadron 130.